Prime Minister John Key is sticking by his coalition partner, Act leader John Banks, but support is waning among those who voted him in.

Banks says the saga over his electoral return and donations ended when police decided not to charge him, but voters in his Epsom electorate say his actions are unacceptable.

The Sunday Star-Times visited Epsom and questioned 30 people who said they voted Banks at the last election. All said they were now embarrassed to have him as their MP because of his actions over his donation declarations during his bid for Auckland's mayoralty, and because of his behaviour once they became public.

Not one offered any support for his position, but all of those spoken to said they were stalwart National supporters who voted Banks to toe the party line and keep Act in Parliament as a coalition partner.

And no matter how unpalatable, those electoral necessities had not changed, Remuera resident Carol Harding, 68, said.

"I feel quite deceived by him after what happened with the donations. But I don't want Key to lose his slim majority. That's a different ball game."

But she said National should consider that there was no way she could vote Banks in 2014.

Fellow Remuera resident Neil Malaghan, 70, also voted Banks.

"I don't know if he should resign, but it's unacceptable, although at the time this all occurred he acted within the law. The police aren't laying a complaint and I have more faith in them than in the judiciary."

But he had the same message for Act and National. There will be no Banks vote in 2014.

Police closed their investigation in July, saying Banks filed a false election return because a $15,000 donation from SkyCity and two $25,000 cheques from German millionaire Kim Dotcom were all registered as anonymous.

But no charges were laid because under one part of electoral law a limitation on the time in which charges could be brought had run out, and under another part of the law, there was insufficient evidence to prove Banks had filed the false return deliberately.

Banks claims he signed the form without reading it and did not knowingly breach the law.

Banks has said in the past: "There has been an expensive police investigation, no charges, all over, all finished and we move on."

But when the police file into its investigation was released, it returned the issue to the spotlight.

The file showed law firm Simpson Grierson partner Gregory Powers spoke to Banks in February, a few weeks after Dotcom was arrested on US anti-piracy charges, and Banks told him he could not offer help to Dotcom because “that may backfire on Kim if it became known about the election support".

Labour deputy leader Grant Robertson told Parliament last week that was "a clear admission he did know about the donation from Dotcom, and could remember it as recently as this year".

- © Fairfax NZ News